> I have a weird problem...
>
> A while ago I wrote some code in VB.NET which gets the block formats from
> mshtml like shown below. I am now converting this into C# and I have the
> problem that the IOleCommandTarget.Exec function doesn't return the
> supported formats - in VB it works fine. (sorry code is long)
>
> Thanks for helping
> Peter
>
> VB code:
>
> Imports System.Runtime.InteropServices
> ' OLECMD
> <StructLayout(LayoutKind.Sequential)> _
> Public Structure OLECMD
>     Public cmdID As Int32
>     Public cmdf As Int32
> End Structure
> ' OLECMDTEXT
> <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)> _
> Public Class OLECMDTEXT
>     Public cmdtextf As OLECMDTEXTF
>     Public cwActual As Int32
>     Private cwBuf As Int32 = 256 'Make sure this is the same as SizeConst
> below
>     <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=256)> _
>     Public text As String
> End Class
>
> Public Enum OLECMDTEXTF
>     OLECMDTEXTF_NONE = 0
>     OLECMDTEXTF_NAME = 1
>     OLECMDTEXTF_STATUS = 2
> End Enum
>
> ' IOleCommandTarget interface
> <ComVisible(True), ComImport(),
> Guid("b722bccb-4e68-101b-a2bc-00aa00404770"), _
> InterfaceType(ComInterfaceType.InterfaceIsIUnknown)> _
> Public Interface IOleCommandTarget
>     <PreserveSig()> Function QueryStatus(ByRef pguidCmdGroup As Guid, ByVal
> cCmds As Int32, _
>     <InAttribute(), Out(), MarshalAs(UnmanagedType.LPArray,
> SizeParamIndex:=1)> ByVal prgCmds() As OLECMD, _
>     <InAttribute(), Out()> ByVal pCmdText As OLECMDTEXT) As Integer
>
>     <PreserveSig()> Function Exec(ByRef pguidCmdGroup As Guid, ByVal nCmdId
> As Int32, _
>     ByVal nCmdExecOpt As Int32, ByVal pvaIn As OLEVARIANT, ByVal pvaOut As
> OLEVARIANT) As Integer
> End Interface
>
> <StructLayout(LayoutKind.Explicit)> _
> Public Class OLEVARIANT
>     <FieldOffset(0)> Public vt As System.Int16
>     <FieldOffset(2)> Public wReserved1 As System.Int16
>     <FieldOffset(4)> Public wReserved2 As System.Int16
>     <FieldOffset(6)> Public wReserved3 As System.Int16
>     <FieldOffset(8)> Public lVal As Integer
>     <FieldOffset(8)> Public iVal As Short
>     <FieldOffset(8)> Public bstrVal As IntPtr
>     <FieldOffset(8)> Public pUnkVal As IntPtr
>     <FieldOffset(8)> Public pArray As IntPtr
>     <FieldOffset(8)> Public pvRecord As IntPtr
>     <FieldOffset(12)> Public pRecInfo As IntPtr
>
>     Public Sub Clear()
>         VariantClear(Me)
>     End Sub 'Clear
>
>     Public Sub LoadString(ByVal Value As String)
>         bstrVal = Marshal.StringToBSTR(Value)
>     End Sub
>
>     Public Function ToNativeObject() As Object
>         Dim p As IntPtr
>
>         Try
>             'Allocate a buffer to hold the data in this OLEVARIANT
>             p = Marshal.AllocCoTaskMem(Marshal.SizeOf(Me.GetType()))
>             Marshal.StructureToPtr(Me, p, False)
>             Return Marshal.GetObjectForNativeVariant(p)
>         Finally
>             'Called no matter what
>             Marshal.FreeCoTaskMem(p)
>         End Try
>     End Function
>
>     <DllImport("Oleaut32.dll", PreserveSig:=False)> _
>     Private Shared Sub VariantClear(ByVal var As OLEVARIANT)
>         ' Leave this blank. Call will be redirected to external DLL.
>     End Sub
> End Class 'OLEVARIANT
>
> Get the formats...
>
> Dim oOut As New OLEVARIANT()
> Dim oIn As OLEVARIANT
> Dim cmdt As IOleCommandTarget
>
> Try
>     Dim pguidCmdGroup As System.Guid = New
> Guid("DE4BA900-59CA-11CF-9592-444553540000")
>     cmdt = DirectCast(HtmlEditor1.Document, IOleCommandTarget)
>     cmdt.Exec(pguidCmdGroup, cmdID,
> onlyconnect.OLECMDEXECOPT.OLECMDEXECOPT_DONTPROMPTUSER, oIn, oOut)
> Catch ex As Exception
>     Throw New Exception("Exec Command: " & ex.Message)
> End Try
>
> C# code:
>
> using System;
> using System.Runtime.InteropServices;
>
> [StructLayout(LayoutKind.Sequential)]
> public struct OLECMD
> {
>     public long cmdID;
>     public long cmdf;
> }
>
> [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
> public class OLECMDTEXT
> {
>     public OLECMDTEXTF cmdtextf;
>     public long cwActual;
>     private long cwBuf = 256; // make sure this is the same as SizeConst
> below
>     [MarshalAs(UnmanagedType.ByValTStr, SizeConst=256)]
>     public String text;
> }
>
> public enum OLECMDTEXTF
> {
>     OLECMDTEXTF_NONE = 0,
>     OLECMDTEXTF_NAME,
>     OLECMDTEXTF_STATUS
> }
>
> [ComVisible(true), ComImport(),
> Guid("b722bccb-4e68-101b-a2bc-00aa00404770"),
> InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
> public interface IOleCommandTarget
> {
>     [PreserveSig()]
>     int QueryStatus(ref Guid pguidCmdGroup, long cCmds, [In, Out]OLECMD
> prgCmds, [In, Out]OLECMDTEXT pCmdText);
>
>     [PreserveSig()]
>     int Exec(ref Guid pguidCmdGroup, long nCmdId, long nCmdExecOpt,
> OLEVARIANT pvaIn, OLEVARIANT pvaOut);
> }
>
> [StructLayout(LayoutKind.Explicit)]
> public class OLEVARIANT
> {
>     [FieldOffset(0)]public int vt;
>     [FieldOffset(2)]public int wReserved1;
>     [FieldOffset(4)]public int wReserved2;
>     [FieldOffset(6)]public int wReserved3;
>     [FieldOffset(8)]public long lVal;
>     [FieldOffset(8)]public int iVal;
>     [FieldOffset(8)]public IntPtr bstrVal;
>     [FieldOffset(8)]public IntPtr bUnkVal;
>     [FieldOffset(8)]public IntPtr pArray;
>     [FieldOffset(8)]public IntPtr pvRecord;
>     [FieldOffset(12)]public IntPtr pRecInfo;
>
>     public void Clear()
>     {
>         VariantClear(this);
>     }
>
>     public void LoadString(String Value)
>     {
>         bstrVal = Marshal.StringToBSTR(Value);
>     }
>
>     public object ToNativeObject()
>     {
>         IntPtr p = IntPtr.Zero;
>         try
>         {
>             // allocate a buffer to hold the data in this OLEVARIANT
>             p = Marshal.AllocCoTaskMem(Marshal.SizeOf(this.GetType()));
>             Marshal.StructureToPtr(this, p, false);
>             return Marshal.GetObjectForNativeVariant(p);
>         }
>         finally
>         {
>             // called no matter what
>             Marshal.FreeCoTaskMem(p);
>         }
>     }
>
>     [DllImport("Oleaut32.dll", PreserveSig=false)]
>     private static extern void VariantClear(OLEVARIANT var);
> }
>
>